Carbonates up to 130 liters of water. SodaStream carbonators, whether used or full, are considered hazardous material by the US Department of Transportation and are subject to special handling rules. UPS and FedEx will not pick up hazardous material (used carbonators) from residences, nor will they accept them at UPS or FedEx stores or drop-off locations. PLEASE NOTE that this decision has no bearing on your ability to exchange carbonators at any SodaStream CO2 exchange retail locations.